"I don't think it's a very widespread thing, but it's sensitive I think would be the word to use. There's a couple of families involved that just make it a bit sensitive."
Mr Forbes said he had "no idea" about the specifics of the sexual allegations.
He said it was disappointing the beach town often hit headlines for the wrong reasons, when there were a number of young people doing "awesome" things.
Opotiki was last in the news for a hit-and-run in the early hours of the morning that killed 14-year-old Rangimaria White in July.
"I don't want to say it's a storm in a tea cup because this stuff's quite serious, but I think there's a very, very, very small number of people involved in it.
"There's so much good stuff going on, and then something bad happens and it's only quite small, and my phone just goes ballistic."
Opotiki College principal Bruce Dale refused to comment on the allegations.
Detective Inspector Mark Loper said police were in the "initial phases of the investigation" and were taking the matter seriously.
Police were providing support to affected students, their families and the school as they investigated the claims.
The sexual allegations, stemming from the latter part of last year, are believed to involve senior boys and junior girls at the school.
"Our priority is the wellbeing of the young people who have provided the information and we have spoken to their families about how we will progress from here."
"Police have allocated all the resources necessary for this inquiry. However, we need to work carefully and methodically, and ask that the community have patience while that occurs."
Anyone with information, or who may be a potential victim, were encouraged to contact police.
It was understood some of the victims may still be attending school with the alleged perpetrators.
An "online component" involved was understood to be a private Facebook page, TV3 reported.
In November 2013, it was revealed a group of young men in West Auckland were using Facebook to brag about their sexual exploits with intoxicated, often underage girls, one as young as 13.
Calling themselves the Roast Busters, the men's activity allegedly occurred between 2011 and October 2013.
Despite a police investigation into the allegations, no charges were brought against the young men.
The police's handling of the complaints was highly criticised and twice investigated by the Independent Police Conduct Authority, which found victims were "let down" by police operations.